/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.springcloud.gray.bean.properties.source;

import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.springframework.util.Assert;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;

/**
 * Maintains a mapping of {@link ConfigurationPropertyName} aliases.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 * @see ConfigurationPropertySource#withAliases(ConfigurationPropertyNameAliases)
 * @since 2.0.0
 */
public final class ConfigurationPropertyNameAliases
        implements Iterable<ConfigurationPropertyName> {

    private final MultiValueMap<ConfigurationPropertyName, ConfigurationPropertyName> aliases = new LinkedMultiValueMap<>();

    public ConfigurationPropertyNameAliases() {
    }

    public ConfigurationPropertyNameAliases(String name, String... aliases) {
        addAliases(name, aliases);
    }

    public ConfigurationPropertyNameAliases(ConfigurationPropertyName name,
                                            ConfigurationPropertyName... aliases) {
        addAliases(name, aliases);
    }

    public void addAliases(String name, String... aliases) {
        Assert.notNull(name, "Name must not be null");
        Assert.notNull(aliases, "Aliases must not be null");
        addAliases(ConfigurationPropertyName.of(name),
                Arrays.stream(aliases).map(ConfigurationPropertyName::of)
                        .toArray(ConfigurationPropertyName[]::new));
    }

    public void addAliases(ConfigurationPropertyName name,
                           ConfigurationPropertyName... aliases) {
        Assert.notNull(name, "Name must not be null");
        Assert.notNull(aliases, "Aliases must not be null");
        Arrays.asList(aliases).forEach(v -> this.aliases.add(name, v));
//        this.aliases.addAll(name, Arrays.asList(aliases));
    }

    public List<ConfigurationPropertyName> getAliases(ConfigurationPropertyName name) {
        return this.aliases.getOrDefault(name, Collections.emptyList());
    }

    public ConfigurationPropertyName getNameForAlias(ConfigurationPropertyName alias) {
        return this.aliases.entrySet().stream()
                .filter((e) -> e.getValue().contains(alias)).map(Map.Entry::getKey)
                .findFirst().orElse(null);
    }

    @Override
    public Iterator<ConfigurationPropertyName> iterator() {
        return this.aliases.keySet().iterator();
    }

}
